Winning form is apparently not enough to placate Walter Smith when he has a grievance. Rangers are now only one win from the Scottish Premier League title but their manager is an angry man. Smith has hit out at both Celtic and the SPL after it was confirmed – amid the complexities of the division's annual split – that Rangers will play Dundee United for a third time away from home in this campaign. The manager is also upset that Rangers' next three fixtures are scheduled away from Ibrox.

Rangers will formally approach the SPL for an explanation. Prominent in Smith's mind are the facts that Celtic complained a year ago regarding Rangers' fixture run-in and, since the split was introduced, Celtic have not played any team away from home three times in one season.

"It is pretty obvious that it is Rangers who have been treated unfairly, not Celtic," Smith said. "There is a hell of an imbalance when you see it. They [Celtic] kicked up a fuss. They were the ones who did the complaining. We have to go to Tannadice three times, it is happening to us nearly every year, yet Celtic have never had to do it.

"In the year we got to the Uefa Cup final [2008], we were told nobody would play three home or three away games in a row. Now, we have three away games in a row: they [the SPL] give us that when it suits them. We have not had an answer about this yet. I hope we will get one."

It is therefore at an away venue for Rangers, Hibernian's Easter Road, that confirmation of Smith's latest championship success could arrive. If Celtic fail to beat Dundee United on Sunday, or Rangers collect three points in Edinburgh, Smith and his players can begin their celebrations.

Hearts had threatened to delay that party after offering stubborn first-half resistance here. Yet the visitors may as well have stayed within their dressing room after the break, such was their second-half lack of invention.

Kyle Lafferty set Rangers on course for victory, the Northern Irishman heading home Kevin Thomson's corner at the near post. Kenny Miller completed the scoring with his 20th goal of the season, from the penalty spot after Eggert Jonsson had bundled Steven Naismith over. As Naismith was poised to tap into an empty net before the foul, Jonsson also received a red card.